The proposed conference is the tenth in a series of Gordon Research Conferences developed from the original conference on cardiac muscle in 1966. At present this series has a three year cycle dealing seriatim with excitation contraction coupling, molecular mechanisms of contraction and problems of membranes with emphasis on electrophysiology. The 1978 conference, for which this application seeks support, is a successor of the 1975 conference with focussed on crossbridge mechanisms. It will deal with the structural basis and molecular mechanisms of contraction and its control; and with the interplay of innervation and muscle activity, on the one hand, and gene expression in muscle, on the other. While the program of the conference will reflect the fact that much of the work on these problems has been carried out on striated muscle, considerable attention will be paid to smooth and cardiac muscle. Investigators from all over the world will discuss recent results obtained with an array of sophisticated tools including electron microscopy, x-ray diffraction, electron spin resonance, fluoroscence and other optical techniques. As in the past, the conference will include more or less formal presentations followed by ample discussion and plentiful opportunities for informal interchange between scientists representing a variety of disciplines such as physiology, biophysics, pharmacology and clinical science. The bringing together for one week representatives of these diverse fields sharing a common interest, viz. muscle, is bound to produce a cross fertilization of ideas resulting in the opening up of new research approaches of far reaching impact.